Instrument adapted to disclose the difference actually existing between pieces whichshould be of the same actual size



F. TURRETTINI.

HE DIFFERENCE ACTUALLY EXISTING BETWEEN PIECES WHICH SHOULD BE OF THE SAME ACTUAL SIZE. APPLICATION FILED FEB. 26. I921. 1,400,331. Patented Deu.13, 1921.

INSTRUMENT AIJAPTEn- IJ DISCL-OSE T .I IN INA! UNITED STATES PATENT OFFICE.

.FERNAND TURRETTINI, OF GENEVA, SWITZERLAND.

INSTRUMENT ADAPTED T0 DISCLOSE THE DIFFERENCE ACTUALLY EXISTING BETWEEN PIECES WHICH SHOULD BE OF THE SAME ACTUAL SIZE.

Specification of Letters Patent. Patented Dec. 13, 1921.

Application filed February 26, 1921. Serial No. 448,236.

To all 4.0 ham it may concern.

Be it known that I, FERNAND TURRETTINI, a citizen of Switzerland, residing at Geneva, Canton of Geneva, in the Confederation of Switzerland, have invented certain new and useful improvements in an instrument adapted to disclose the difference actually existing between pieces whichshould be of the same actual size, of which the following is a specification.

The object of the present invention is an instrument adapted to disclose with an extremely great precision the difference actually existing between pieces which should be of the same actual size.

The instrument canalso be used as a contact indicator showing by the displacement of its index needle very accurately the position or the moment in which it enters into contact withany other body. 7

The instrument comprises an anvil acting upon a rocking lever having two arms of very unequal length, the short arm being connected to the anvil and the long one carrying an index or forming itself an index, marking on a scale the position of the'lever. The anvil works upon the lever by means of a knife edge. The rotating axis of the lever is represented by another knife edge. This arrangement is adapted to reduce the friction caused by the rocking of the lever to a minimum.

In order to make sure that. this friction becomes a real minimum another additional.

condition requires consideration, namely: when the rocking system is in 1ts mean posltlon the edges of both kmves should be in the same plane perpendicular to the axis of the anvil.

In the drawing F igure l, is a central longitudinal cross section of part of the apparatus forming my present invention.

Fig. 2, is a cross section of the same parts taken at right angles to the position as illustrated in Fig. l. y

Fig. 3,-is an elevation and'partial cross section of another part of the apparatus.

Fig. 4:, is a plan view of the parts of the apparatus shown in Fig. 3.

Fig. 5, is an elevation and partial cross section of the same parts as shown in Fig. 3, taken at the position 90 degrees from those shown in Fig. 3.

Fig. 6, is an elevation and partial cross spring section of apparatus with the parts assembled and Fig. 7 is a similar view showing the indicator of the apparatus in a different position.

In Figs. 1 and 2 which represent only a portion of the instrument a is the anvil of which the extremity b constitutes the measuring face. A fork shaped member 0 is fixed upon theanvil. The prongs d and e of said fork c are connected by a knife whose edge f, interrupted in its middle portion, constitutes one of the pivoting points of the rocking system. Since the fork 0 carrying the edge f is rigidly fixed upon the anvil a, said edge f will be subjected to all the movements which the face I) of anvil a will make. A spring 9 tends constantly to push the anvil out of the body it of the instrument. Another knife 1' is carried by a member s which latter is adapted to slide in a plane perpendicular to the axis of the anvil. The two screws 6 and t advancing in opposite directions are provided for displacing said member s laterally and to thereby regulate the distance a between the knife edges 7' and f in a plane perpendicular to the axis of the anvil.

According to Figs. 2, 3, 4 and 5, the rocking member comprises a plate i, having a central hole j and in suitable ledges a triangular groove 70 the apex of which is exactly in the plane of the face m of plate A second plate a of very hard metal is tightly secured upon the face we of plate Therefore the bottom face 0 of plate a, which face is in close contact with the top face m of plate 2', is also in the plane passing through the apex of the triangular groove 7cl. Upon the plate i the index needle 7) and a q is fixed which tends to lift the plate 2'. p

If the rocking portion is put on the bottom part of the instrument in such a manner that the knife edge f bears into the groove kZ of plate i (Fig. 6) and that the edge of knife 7' bears on the face 0 of plate 12, a small lateral distance u being provided for between said two edges, 7, r, in the direction opposite the side to which the spring 9 is fixed, then the whole rocking system which is under the action of the springs g and 9 but is retained by the knives f and r will usually be in perfect equilibrium.

The angle between the index needle 29 and a plane perpendicular to the axis of the anvil 0/, depends upon the distance w (Fig. 7) in the direction parallel to the axis of the anvil a. If the anvil is moved, the distance to will be altered and theindex needle will assume a new steadied position of equilibrium.

The angular range of motion of the index needle 29, being small and symmetric to its mean position, in which the bottom face 0 of plate a is perpendicular to the axis of the anvil a the displacements of the index needle p will be very closely proportional to those of the anvil. V w

It'will be observed that an excessive displacement of. the anvil cannot cause-a damage to the instrument, although the angular range of the rocking system israther small. If the distance to becomes excessively great (Fig. 7 the spring only acts upon the rocking system, which is not subjected to any other prejudicial strains. When the distance to does exceed a given limit,the face 0 of plate nv will simply cease to bear upon the edge of knife 7'.

The multiplying capacity of'the instrument depends upon the ratio ofthe length of the index needle 2) to the adjustable distance a (Figs. 1 and 2). Therefore the multiplying capacity of the instrument according to invention may be chosen at will.

The whole instrument, except the projecting end of the anvil a, may be inclosed in a protective tubular case, a suitably arranged glass plate making it possible to v read the indications of the scale (Figs. 6

V and 7.)

I claimas my invention I I r 1 1. In a needle lndicator and'in combination a body member, a measuring anviladapted to slide within saidbody mem' ber, a spring for actingupon said anvil, a knife rigldly connected to said anvil, a rocklng lever having two arms of unequal length, thelonger one being adapted for serving as an lndex, a second knife, means,

for adjusting said second knife,a plate having a groove adapted for receiving the edge of the knife rigidly connected to the anvil, a second plate tightly fixed upon said first plate, the apex of the groove in said first plate being in the plane passing through the bottom surface of said second plate and through the edge of said adjustable knife, substantially as described' 2. In a needle indicator andin combination a body member, a measuring anvil adapted to slide within said body member,

a spring for acting upon said anvil, a knife rigidly connected to said anvll, a rocking an index, a second knife, means for adjusting said second knife, a plate? having a groove being adapted to receive the edge of the knife rigidly connected tothe anvil, a

second plate fixed upon said first plate, the

apex of the groove in said first plate being in the plane passing through the bottom: surface, of said second plate and through the edge of said adjustable knife, the edges of both lmiveslbeingdirected one against the other, said edges being adapted to be separated from one another when the anvil touches any piece to be measured, the rockingdevice being adapted to remain in contact with the knife edges, by means of a spring, to avoid damaging the instrument in the event of an excessive or abrupt displacement of the measuring anvil, substantially as described. w

3. In a needle indicator in combination a body member, a measuring anvil adapted to slide within said body member, a spring for acting upon said anvil, a' knife rigidly connected to said anvil, a rocking lever having two arms of unequallength, the longer one being adapted for serving as anindex, a second knife, means for adjusting said second knife, a plate'having a groove adaptedto receive the edge of the knife rigidly connected to the anvil, a second plate fixed upon said first plate, the apex of the groove in said first platebeing in the plane passing through the bottom surface of'said second plate and through the edge of said adjustable knife, the edges of both knives being directed one against the other, said edges being adapted to be separated from one another when the anvil touches any piece to be measured, the rocking device being adapt:

.signature in presence of two witnesses.

FERNAND TURRETTINI. Witnesses:

DnRoD. DE WURTEMBERG, CHAS. A. SoHLnGLE. 

